Dataset Information

Diurnal adult resting sites and breeding habitats of phlebotomine sand flies in cutaneous leishmaniasis endemic areas of Kurunegala District, Sri Lanka.

ABSTRACT: BACKGROUND:Sand flies are responsible for the transmission of several disease pathogens including Leishmania. Sand flies breed in habitats with high levels of humidity and organic matter. They are nocturnal in nature and peak activity ranges from dusk to dawn. The scientific evidence on breeding ecology and diurnal resting sites of sand fly fauna are important aspects of planning and implementing vector control activities. However, such fundamental information is grossly inadequate in Sri Lanka to support the control efforts in the country. Therefore, the present study addresses some of the important aspects of sand fly breeding ecology and diurnal resting sites. METHODS:Potential resting sites were thoroughly observed, and sand flies were collected using a battery-operated aspirator and sticky papers when appropriate from three selected Medical Officer of Health (MOH) areas (Polpithigama, Maho and Galgamuwa) in Kurunegala district, Sri Lanka. Soil samples were collected from each potential breeding site. Half of each soil sample was incubated for 45 days. The other half was screened for immature stages. Adult sand flies collected from field and emerged adults at the insectary under confined incubation were identified using morphological characteristics. RESULTS:Pepper bushes and termite mounds were the most notable resting sites while, betel bushes, cattle huts, piles of coconut shells, latrines, manna bushes and tree holes were also positive for sand fly adults. Only two species, Phlebotomus argentipes and Sergentomyia punjabensis, were reported. Soil samples were collected from a total of 432 sites and 7 of them were positive for immature stages. Predominant breeding habitats identified during the present study were mud flats and moist soils of rice paddies, the soil below decaying hay, drying irrigational tank bottom moist soil, and the floors of cattle huts. CONCLUSION:This study demonstrates that the potential adult resting sites and breeding habitats are abundant in the Polpithigama, Maho and Galgamuwa MOH areas. Therefore, vector control activities targeting both adult and immature stages of sand flies are recommended.

SUBMITTER: Wijerathna T

PROVIDER: S-EPMC7275303 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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Diurnal adult resting sites and breeding habitats of phlebotomine sand flies in cutaneous leishmaniasis endemic areas of Kurunegala District, Sri Lanka.

Wijerathna Tharaka T Gunathilaka Nayana N

Parasites & vectors 20200605 1

<h4>Background</h4>Sand flies are responsible for the transmission of several disease pathogens including Leishmania. Sand flies breed in habitats with high levels of humidity and organic matter. They are nocturnal in nature and peak activity ranges from dusk to dawn. The scientific evidence on breeding ecology and diurnal resting sites of sand fly fauna are important aspects of planning and implementing vector control activities. However, such fundamental information is grossly inadequate in Sr ...[more]

PMID: 32503610

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Project description:BackgroundLeishmaniasis is a notifiable disease in Sri Lanka since 2008. Previous studies show a gap in the notification of leishmaniasis. The purpose of the present study was to determine the Knowledge, attitudes and practice of medical officers regarding leishmaniasis.MethodsA cross-sectional study was conducted in the Anuradhapura district which reported the highest case load of leishmaniasis. Medical officers from public and private health care institutes in the area filled a self-administered questionnaire in the presence of the investigators.ResultsOne hundred and eighty-eight (188) medical officers completed the questionnaire. Of them, 95.7% were aware of leishmaniasis as a parasitic infection and 84.7% correctly identified Leishmania donovani as the causative organism in Sri Lanka. From the respondents, 181 (96.8%) knew that the vector of leishmaniasis is sand fly. Cutaneous leishmaniasis was reported as the most prevalent form of leishmaniasis in the country by 176 (94.1%). Nearly half of the respondents (98, 54.1%) were aware of the fact that the Anuradhapura district has the highest disease burden. Many of them had the idea that leishmaniasis is an emerging disease (155, 84.3%,) and early diagnosis is important in controlling the disease (163, 89.1%). Although about three fourth (123, 73.7%,) of the participants mentioned that leishmaniasis should be notified at first clinical suspicion, only 74 (42.5%) were aware that it is a legal requirement. Some medical officers (39, 22%) believed that the current notification system in the country is not effective. Unavailability of notification forms (60, 36.8%) heavy workload (85, 50.3%) and inadequate supportive staff (55, 35.1%) were reported as barriers for timely notification. Even though 105 (58.0%) of medical officers had suspected leishmaniasis during the last 8 years period only 35 (19.4%) had notified.ConclusionsEven though more than 90% of the participants had good theoretical knowledge about leishmaniasis; notification of leishmaniasis is considerably inadequate. This study emphasizes the need for greater efforts to improve the notification of leishmaniasis in Sri Lanka.

Project description:BackgroundLeishmania donovani-induced and sand fly-transmitted leishmaniasis is a growing health problem in Sri Lanka. Limited knowledge on biological and behavioral characteristics of probable vector Phlebotomus argentipes hinders disease control. Here, insecticide susceptibility patterns of P. argentipes were investigated with exploration of probable underlying resistance mechanisms.MethodsAdult sand flies were collected using standard cattle baited net traps and CDC light traps from selected sites in four districts. Adult F1 progeny of P. argentipes were exposed to different concentrations of DDT, malathion, deltamethrin and propoxur using WHO susceptibility bioassay kits. Post-1-h knockdown and post-24-h mortality were recorded and analyzed. Metabolic enzyme activity and the sensitivity of the acetylcholinesterase target-site were determined by biochemical assays using wild-caught flies. Extracted fly DNA samples were tested for the presence of knockdown-resistance (kdr) type mutations.ResultsThe LC100 values for DDT, malathion, propoxur and deltamethrin were 0.8-1.5%, 0.9-2.0%, 0.017-0.03% and 0.007% respectively. Insecticide-susceptibility levels were higher than the discriminating dosages established for Aedes mosquitoes, except for malathion. The lowest susceptibility levels (except for deltamethrin) were detected in the Mamadala population, whereas the highest levels were detected in the Mirigama population. The percentage of knocked-down sand flies was < 75% at any tested concentration, including those, which exhibited 100% mortality after 24 h. Elevated activity levels of glutathione S-transferase (3%, 7%, 12.5% and 14%) and esterase (2%, 5%, 5.5% and 6.5%) were detected in flies that originated from Mirigama, Pannala, Thalawa and Mamadala respectively, while monooxygenase quantities remained below the cut-off level. Ten to 34.5% of flies were heterozygous for acetylcholinesterases target-site insensitivity, associated with organophosphate and carbamate resistance. Pyrethroid-resistance-associated L1014F kdr-type mutation in the voltage gated sodium channel gene was detected in 30/53 flies.ConclusionsPopulations of P. argentipes in Sri Lanka are largely susceptible to common insecticides, except for malathion (used extensively in the past for malaria control). Their insecticide susceptibility appears negatively associated with past malaria endemicity of the study sites, with signs of early insecticide tolerance. Presence of insecticide target site insensitivity in a notable proportion of flies and enhanced insecticide metabolizing enzyme activities imply potential future challenges for leishmaniasis control, with a call for urgent proactive measures for its containment.

Project description:Sri Lanka records substantial numbers of snakebite annually. Primary rural hospitals are important contributors to health care. Health care planning requires a more detailed understanding of snakebite within this part of the health system. This study reports the management and epidemiology of all hospitalised snakebite in the Kurunegala district in Sri Lanka.The district has 44 peripheral/primary hospitals and a tertiary care hospital-Teaching Hospital, Kurunegala (THK). This prospective study was conducted over one year. All hospitals received copies of the current national guidelines on snakebite management. Clinical and demographic details of all snakebite admissions to primary hospitals were recorded by field researchers and validated by comparing with scanned copies of the medical record. Management including hospital transfers was independently assessed against the national guidelines recommendation. Population rates were calculated and compared with estimates derived from recent community based surveys.There were 2186 admissions of snakebites and no deaths in primary hospitals. An additional 401 patients from the district were admitted directly to the teaching hospital, 2 deaths were recorded in this group. The population incidence of hospitalized snakebite was 158/100,000 which was significantly lower than community survey estimates of 499/100,000. However there was no significant difference between the incidence of envenomation of 126/100,000 in hospitalised patients and 184/100,000 in the community survey. The utilisation of antivenom was appropriate and consistent with guidelines. Seventy patients received antivenom. Anaphylactic reactions to antivenom occurred in 22 patients, treatment reactions was considered to be outside the guidelines in 5 patients. Transfers from the primary hospital occurred in 399(18%) patients but the majority (341) did not meet the guideline criteria. A snake was identified in 978 cases; venomous snakebites included 823 hump-nosed viper (Hypnalespp), 61 Russell's viper, 14 cobra, 13 common krait, 03 saw scaled viper.Primary hospitals received a significant number of snakebites that would be missed in surveys conducted in tertiary hospitals. Adherence to guidelines was good for the use of antivenom but not for hospital transfer or treatment of anaphylaxis. The large difference in snakebite incidence between community and hospital studies could possibly be due to non-envenomed patients not presenting. As the majority of snakebite management occurs in primary hospitals education and clinical support should be focused on that part of the health system.

Dataset Information

Diurnal adult resting sites and breeding habitats of phlebotomine sand flies in cutaneous leishmaniasis endemic areas of Kurunegala District, Sri Lanka.

Publications

Diurnal adult resting sites and breeding habitats of phlebotomine sand flies in cutaneous leishmaniasis endemic areas of Kurunegala District, Sri Lanka.

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